吡咯, 噻酚和呋喃的情况就是这样.Such is the case in pyrrole, thiophene, and furan.研究结果表明关键步骤为原料 4- 甲基 -2, 3- 呋喃二酮的合成.It'shows that the key step is the synthesis of 4 - methyl - dihydro - furan - 2 , 3 - dione.用糠醇和糠醛缩聚制备了新型呋喃树脂.A n...
Vicki : The Gherkin is three times as tall as Niagara Falls.它的高度是尼亚加拉瀑布的三倍.The Niagara Falls is one of the natural wonders of the world.尼亚加拉瀑布是世界天然奇景之一.Niagara Falls is one of the greatest marvel in the world.尼亚加拉瀑布是世界大奇...
这些纸用来封住墙壁和屋顶的洞。The paper was used for sealing up holes in walls and roofs.石料开始被用作盖屋顶的材料。Stone began to be used as a roofing material.我们从屋顶的小洞能看见星星。We could see the stars through an opening in the roof....